[cyphar]

The backdoor problem is a serious issue, but TCNs aren't necessary for email providers. All your emails are already I'm plaintext.

I'd be more worried about the fact that TARs and TANs have no judicial overview and are secret in a way that other kinds of warrants aren't. But then again, you aren't the one being served with a warrant.

As an Australian, I wouldn't use it anyway. Mailbox.org is better IMHO, and is what I use.